There’s always plenty of vengeance afoot on Game of Thrones, but now the acclaimed HBO drama is about to get a dose of The Avengers. The network announced this afternoon at Comic-Con that Diana Rigg will join the cast as Lady Oleanna Tyrell, better known as the Queen of Thorns.

The show’s Season 3 premiere is set for March 31, and 13 additional actors have been cast, producers announced. They include: